Control system for electric motors.



J. H. HALL.

CONTROL SYSTEM FOR ELECTRIC MOTORS.

APPLICATION FILED MAR.18, 1910.

Patented July 18,1911.

WITNESSES \NVENTUR W /L My), rad/um,

QQMMM UNITED STATES PATENT OFFICE.

JAY H. HAIiL, OF CLEVELAND, OHIO, ASSIGNOB TO THE ELECTRIC CONTROLLERAND MANUFACTURING COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

CONTROL SYSTEM FOR ELECTRIC MOTORS.

Specification of Letters Patent.

To all whom it may concern.

Be it known that- I, JAY H. HALL, a citizen of the UnitedStates,-residing at Cleveland, in the county of Guyahoga and State ofOhio, have invented or discovered new and useful Improvements in ControlSystems for Electric Motors, of which the following is a specification.

My invention relates to systems for controlling motors and hasparticular reference to the-control of the motors used with hoists, butis not limited to such use.

It is the principal object of my invention to rovide such circuits forthe motor as wil secure high maximum speeds for driving light loads-downand, to obtain a safe maximum speed for lowering such heavy loads asoverhaul the motor anddrive it as a generator.

It has been proposed to place a non-variable resistance in series withthe armature branch-of a 'motor circuithaving the field in a parallelbranch of the motor circuit, so

that, when the master-controller is on the last lowering position, thesaid resistance would prevent the armature from attaining its highestspeed when driving the load down and would allow the armature to run ata hi her than normal speed on heavy loads w en such load drives the'motor as a nerator.

' t is the object of my invention to gradually short-circuit thisresistance, or eliminate the efiects of the same from the motor circuitas the. controller is moved toward its full-on position in the loweringdirection, until finally the armature terminals are connected directlyacross the supply mains.

Referring to the accompanying drawings, Figure 1 is a diagramillustratingthe various conditions when the master controller is in theoil-position; and Figs. 2, 3, 4, and 5 are sim lified diagrams of themotor cir-- cuits w en the master controller is, respectively, in'thefirst hoisting position, the first lowering position, the final loweringposition, and the off-position.

Fig. 1' shows conventionally the armature A, its series field F, theseries winding B of the brake B, the magnetic switches D and H, therheostatic resistances R and R controlled in an evident manner by themaster controller C, and the resistance R? which I Patented July 18,1911.

gradually short circuit as the master con troller is moved in thelowering direction.

To hoist a load, the controller arm 0 is placed in the first positionhoisting, at

Which time the brushes 0" and 0 connect the se ent c to the contact 0and the segment 0 to the contact a. A circuit is now established throughthe operating solenoid h of the switch H as follows: from the positivethrough the wire 18, the sole 'noid k, the wire 19, the contact a, thebrush 0, the contact 0 the cross connection to the contact 0 theresistance R, the wire 10, the blow-out coil 0, and the wire 11 to thenegative,

circuit as follows: from the positive through the wire 1, the switch H,the wires 2nd 3, the armature A from left to right, the wires Thecurrent in this circuit causes the switch H to close, establishing themotor 4 and 5, the contact a thecross connection to the contact 0 theresistance R, the con- 7 tact a, the cross connection to the contact 0,the wire 6, the series field F, the wires 7 and 8, the brake winding B,the wire 9, the contact a, the resistance R, the wire 10, the

blow-out coil 0", and thewire 11 to the negative. The motor is by thiscircuit connected across the line in series with the resistances R" andR, which circuit is shown in Fig. :2. v

The 'varlation of speed in hoisting is' accomplished by means of plainrheostatic control. As the controller arm a" is moved toward thefull-onposition, the resistances R, and R gradually short-circuited thefull-on ition is reached, at which time the motor is connected directlyacross theline. 7

It is understood that as soon as the current passes through the brakewinding B the brake is released, which allows the motor to rotate; andsince the winding. B is at all times connected in series with the field'of the motor when. the motor circuit is connected to the source ofsupply, the brake will be held released. When it is desired to stop theload in hoisting, the controller arm is moved to the off-position, whichoperation gradually inserts the resistances R and B. into the motorcircuit, this circuit being finally'broken at the oil-position, when the.brake winding B is deenergized and the the wire 9 to the contact 0brake permitted to set.

To operate the motor in a direction opposite to that in hoisting, thecontroller arm 0 is moved to the first position on the lowering side ofthe controller, where the brush 0 connects the contacts 0 c and 0 andthe brush 0 connects the contacts 0 and A circuit is now establishedthrough the operating solenoid d of the switch D as follows: from thepositive through the wire 18,

the solenoid d, the wire 20, the contact 0 the brush 0", the contact 0the resistance R, the wire 10, the blow-out coil 0 and the wire 11 tothe negative. The current in this circuit closes the switch D, thefollowing motor circuit being established: from the positive through thewire 1, the switch D, and the wire 12 to the point 0. Here the circuitdivides, one branch being through the field F of the motor, and theother through the armature A, the field branch passing through the wire13, the contact 0, the brush 0 the contact 0 the wire 6, the seriesfield F in the same direction as in hoisting, the wires 7 and 8, thebrake winding B, and Here the circuit just traced is joined by thebranch circuit through the armature which latter circuit passes from thepoint .0 through the wire 14, the resistance R the wires 15 and 4, thearmature A from right to left, the wires 3 and 16, the contact 0 thebrush 0, and the contact a where the two branches of the circuit unite.The circuit is completed from the contact 0 through the resistance R,the wire 10, the blow-out coil 0, and the wire 11 to the negative. Thesimplified motor circuit just described is shown diagrammati cally. inFig. 3.

The resistance R is in parallel with resistance R but since theresistance R is a preventive resistance and much smaller than theresistance R the greater portion of the current will pass through theresistance B. As the controller arm is moved'toward the full-on positionthe result is to gradually insert the resistance'R in the field branchof the circuit, and at the same time to reduce the amount of theresistance R which is in parallel with the resistance R until, at thefull-on position, all of the resistance R is placed in the field circuitand the resistance R is short-circuited. At the same time the resistanceR is cut out of the armature circuit and inserted in the dynamic brakingcircuit, so that, on the final full-on position, the armature isconnected directly across the supply mains and the field is connecteddirectly across the supply mains in series with the resistances R and R.

With the controller arm in the full-on position in the loweringdirection, the arma- .ture circuit (Fig. 4) is as follows: from thepositive through the switch D, the wires 12 and 13, the contact a, thebrush 0, the contact 0 the wires 5 ands, the armature A, the wires 3 and16, the contact 0 the brush 0, the contact 0 the wire 10, the blow-outcoil 0, and the wire 11 to the negative. The

circuit through the field is as follows: from the positive through thewire 1, the switch D, the wires 12 and 13, the contact 0, the brush 0the contact 0 the cross connection to the contact a, the resistance Rthe contact 0 the cross connection to the contact 0 the wire 6, thefield F, the wires 7 and 8, the brake winding B,- the wire 9, thecontact 0 the resistance R, the wire 10, the blow-outcoil 0 and the wire11 tothe negative. To reduce the speed in lowering, the controller arm 0is moved toward the oi"- position, which reverses the relation of theresistances to the motor circuit in the above description, the motorbeing slowed down reference to Fig. 3, to contain the armature,

the series field, and the brake winding B in series with the resistanceR It the controller arm 0 is moved from the lowering to the offposition, the connection to the brake is such that the brake coil is cutout of the dynamic braking circuit and the motor circuit is disconnectedfrom the supply mains, as shown in the simplified circuit in Fig. 5,which allows the brake: to set and assist the dynamic braking circuit tostop the load.

li do not limit my invention to series wound motors or brakes, nor toany definite type of controller, nor to other details and combinationsthereof unless required by the prior art or by language in the claimswhich permits of no other construction.

1. In an electric control system, a motor, two resistances for limitingthe current in the armature circuit, the resistances having a commonpermanent connection with one terminal of the armature, and at least oneof saidv resistances being variable, movable contacts cooperating withthe variable resistance to cause the current in the said otherresistance to decrease and the current in the part of the variableresistance adjacent to the said other resistance to increase.

2. Inan electric control system, a motor, two resistances for limitingthe current in the armature circuit, the resistances having a commonpermanent connection with one terminal of the armature, and at least"one of said resistances being variable, and movable contacts forcoeperating with the variable resistance, said contacts being soconnected that at one-position thereof the two resistances are inparallel, and as the contacts are moved toward the other limit of theirtravel, the amount of the variable resistance in parallel with the otherresistance becomes smaller.

3. In an electric control system, a motor, a resistance connectedbetween the armature and field windings, a second resistance connectedin parallel with the first resistance, andmeans for causing an increaseof voltage on the armature and a decrease of voltage on the field byreducing the amount of the first mentioned resistance in parallel withthe second resistance.

4. In an electric control system, a motor, two resistances having acommon connection, a motor armature having one terminal connected to thesaid common connection, and means for connecting the remaining end ofone resistance to a source of supply and to various points on the other.

5. In an electric control system, a motor, means connecting the armatureand field windingsof the motor in parallel branches, a variableresistance in the field branch, a fixed resistance in parallel with thevariable resistance, and means for decreasing the amount of the variableresistance in parallel with the fixed resistance.

('3. In an electric control system, a motor, two resistances, meansconnecting the armature and field windings of the motor to .the sourceof supply in parallel aths, low resistance in series with said pat s,and means for lncreasing resistance in the parallel circult, increasingthe resistance between the field winding and the source of supply, and

decreasing resistance between the armature and the source of supply.

7. In an electric control system, a motor,

means connecting the armature and field windings of a motor in parallelbranches, two resistances in parallel in the armature branch, and meansfor cutting portions of one resistance out of parallel with the otherreslstance and inserting said portions in the field branch.

8. In an electric control system, a motor, means connecting the armatureand field windings in parallel branches to the supply mains, aresistance in series with said branches, a relatively small resistancein the branch circuit containing the armature, and

means for increasing resistance in the field branch and decreasingresistance in the armature branch until the-small resistance 1sshort-circuited' and the armature is connected directly across thesupplymains.

9. In an electric control system, a motor,

means connecting the armature and field windings in parallel paths, afixed and a variable resistance in the armature path, and means by whichthe said fixed resistance is short-circuited to cause an increase ofvoltage on the armature'and a decrease of supply mains, a fixed and avariable resistance in circuit therewith, and means by which thevariable resistance is cut out of the armature branch and inserted inthe field branch and the fixed resistance is shortcircuited.

11. In an electric control system, a motor, two resistances, oneresistance having one terminal connected to the field and the otherterminal connected to the armature and to one terminal of the secondresistance, and means connecting the other terminal of the secondresistance to various points on the first resistance.

12. In an electric control system, a motor, a resistance connectedbetween the armature and the field of a motor, a second resistancehaving one end connected to the source of supply, and the other end toone terminal of the first resistance, and means connecting the source ofsupply to various points on the first resistance.

13. In an electric control system, a motor,

means connecting the armature and the field windings of the motor 'inparallel branches, a fixed resistance in one branch and variableresistance in parallel with the fixed resistance, and means fortransferring the variable resistance to the other branch.

14. In an electric control system, a motor,

means for connecting the armature and the I field ofthe motor inparallel branches, a resistance in one branch, "a variable resistance inparallel therewith, and means for gradually transferring the variableresistance to the other branch and for short-circuiting the otherresistance.

15. In an electric control system, a motor, means for connecting thearmature and the field windings of the motor in parallel branches, tworesistances in parallel in the armature branch, means for gradually andsimultaneously transferring'one of the resistances to the field branchand for shortcircuiting the other resistance.

16. In an electric control system, a motor, resistance connected betweenthe armature and the field windings, means for connecting the armatureand the field in series across a source of supply to operate the motorin one direction, and means for connectin a second resistance in arallelwith the rst resistance-to operate t e motor in the reverse directionand for reducing the amount of the first mentioned resistance inparallel with the second resistance to vary the speed of the motor.

17. In an electric control system, a motor,

a variable resistance connected between the armature and the fieldwindings, means f r connecting the armature, thefield, and'th resistancein series to o erate the motor in one direction, means or connecting thearmature and field windings in parallel branches, the resistance beingin one branch and in parallel with the second resistance to operate themotor in the reverse direction, and means for short-circuiting thesecond resistance. I

18. In an electric control system, a motor,

7 a variable resistance connected between the armature and the field ofa motor, afixed .LO resistance having one terminal connected to Signedat Cleveland, Ohio, this 2nd day 1:3

of March, 1910.

JAY H. HALL. Witnesses HENRY L. 1 .ssu'r,

WV. M. DIEMER.

